In a wireless multiple access communication system, wireless terminals contend for system resources in order to communicate with a common receiver over an uplink channel. An example of this situation is the uplink channel in a cellular wireless system, in which wireless terminals transmit to a base station receiver. When a wireless terminal transmits on the uplink channel, it typically causes interference to the entire system, e.g., neighboring base station receivers. Since wireless terminals are distributed, controlling the interference generated by their transmission is a challenging problem.
Many cellular wireless systems adopt simple strategies to control uplink interference. For example CDMA voice systems (e.g., IS-95) simply power control wireless terminals in such a manner that their signals are received at the base station receiver at approximately the same power. State-of-the-art CDMA systems such as 1×RTT and 1×EV-DO allow for wireless terminals to transmit at different rates, and be received at the base station at different powers. However, interference is controlled in a distributed manner which lowers the overall level of interference without precisely controlling those wireless terminals that are the worst sources of interference in the system.
This existing body of interference-control approaches limits the uplink capacity of wireless systems.
It would be useful if a base station could be provided with information that could be used in determining the amount of signal interference that will be created in neighboring cells when a transmission occurs and/or the amount of interference a wireless terminal is likely to encounter due to signal interference. It would be particularly desirable if information which can be used for interference determination purposes could be supplied by one or more wireless terminals to a base station.